Clinical and necropsy observations are described in 40 patients (29 women) aged 90 years and older. The majority (21 patients [57%]) died during the 4 coldest months, and 12 (30%), during the 4 warmest months. At necropsy, 39 had greater than or equal to 1 major cardiac abnormalities, the most frequent being calcific deposits in the major epicardial coronary arteries in 37 (92%). In 28 patients (70%), 1 or more of the 4 major arteries was narrowed 76 to 100% in cross-sectional area (XSA) by atherosclerotic plaques, an average of 1.9/4.0 per patient: the 12 patients with clinical events compatible with myocardial ischemia (angina pectoris or myocardial infarction) had an average of 2.2/4 and the other 28 patients an average of 1.0/4.0. In 36 patients, a histologic section was examined from each 5 mm long segment from each of the 4 major coronary arteries: of the 1,789 segments, only 6 (less than 1%) were narrowed 96 to 100% in XSA by plaques; 147 (8%), 76 to 95%; 339 (19%), 51 to 75%; 930 (52%), 26 to 50%, and 367 (21%), 0 to 25%. The average amount of XSA narrowing for the 1,789 segments was about 42%. In 10 patients with clinical evidence of myocardial ischemia, the average amount of narrowing per segment was approximately 55%; in the 26 patients without clinical ischemia, the average was about 38%. Of the 40 patients, 18 (45%) had left ventricular transmural foci or fibrosis or necrosis or both. Of 14 patients with transmural scars, only 1 had a clinical event compatible with acute myocardial infarction; of the 10 with acute myocardial infarction at necropsy, only 4 had typical clinical features of infarction. Thus, cardiovascular disease was present at necropsy in 39 of our 40 patients, but frequently it was not diagnosed clinically.